Generally, a mobile network is comprised of many base stations and each base station may serve one or more cells. Each cell in a mobile network may be associated with two identifiers: (1) a physical layer cell identifier (PCI) and (2) a global cell identifier (GCI). Because the number of PCIs is limited, PCIs are not globally unique. That is, it is possible that two cells within a given mobile network (e.g., a public land mobile network (PLMN)) may have the same PCI. On the other hand, GCIs are globally unique. That is, for example, no two cells within a PLMN will have the same GCI.
Each cell in the mobile network may have multiple neighbors. For each particular cell, it is advantageous to compile and maintain a neighbor cell “list,” which is also known as a “neighbor cell relation,” (e.g., a database, ordered list, unordered list, or other collection of information) of the cells that neighbor the particular cell. A neighbor cell list for a particular cell contains the PCI and GCI of each cell that neighbors the particular cell. This neighbor cell list may be used by the base station that serves the cell to communicate with other base stations that server the neighbor cells.
One way to compile and maintain a neighbor cell list for a particular cell is to manually create and update the list. However, it is preferred to have systems and methods for automatically updating the list. One way to automatically update the list is to request a mobile terminal (a.k.a., user equipment (UE)) using the particular cell to obtain the GCI of a neighboring cell and report the GCI to the base station that serves the particular cell. A problem with this approach is that it may take a relatively long period of time for the UE to obtain the GCI and while the UE is attempting to obtain the GCI the UE may not be able to receive data from the base station.
What is desired are improved systems and methods for automatically determining the global cell identifier (GCI) of a neighboring cell.